Figure 8
The pre-test result for the orthogonal design, which shows the selected 3 levels for each factor with a black box. \({\Delta E}_{00}\) is the color difference between data from DIS and date from photo calibration calculated by Eq. (9). The box is the range for the subsequent Orthogonal Design, the reason for the selected levels is based on the lowest \({\Delta E}_{00}\) and China national standard GB/T 26189-2010 “Lighting of Indoor Workplaces” and GB/T 23885-2009 “Jadeite grading”. From top to bottom: Exposure Time, Measurement Distance, Illuminance.
